It's generally believed that the number one product from California's number one industry isn't legal. Agriculture remains the Golden State's biggest business, and some believe marijuana is worth $14 billion. No one really knows for sure.

The LEGAL medical marijuana business is estimated by advocates to be worth up to $2 billion. Legal, that is, in the state's eyes. It's still illegal under federal law.

Today I'm reporting on the business of selling pot legally, the costs and challenges that go with it. Twelve years after California was the first state to make medical marijuana legal, many clinics are still raided as criminal enterprises (and some are--even under state law), and many others remain paranoid, having come from an underground culture that has pervaded the industry for so long.

Then there are those pushing for openness, transparency, ethics, and standardized practices. In the face of almost no regulatory standards, they're developing their own, and making money doing so.

One company, Oaksterdam University (a combination of its hometown of Oakland and Amsterdam) is charging people $200 to take classes and be tested to achieve "certification" as a grower or clinic owner. There's a company that will even certify your marijuana as "green," grown to organic standards. The USDA, of course, can't do this.

But not everyone in California is on board. Some counties are reportedly suing the state so they don't have to issue identification cards to medical users.

Still, the state has seen a fivefold increase in clinics in the last few years. Some offer only a few choices, but Oaksterdam's Danielle Schumacher says other clinics offer up to a hundred different varieties watched over by a dozen "bud tenders." Teaching these bud tenders is part of Oaksterdam's goal. As Schumacher says, "somebody's gotta do something about this."